I recently watched one of the most brutal and upsetting films I’ve ever seen, called The Stoning of Soraya M. I suppose the title of this 2008 film should have warned me away, but I really don’t believe that anything could prepare viewers for the graphic, bloody and excruciatingly prolonged scene that gives the film its name. It’s the story of a 35-year-old mother, falsely accused of adultery by her bullying husband and local mullah, who is convicted under Islamic law and executed by the men of a rural Iranian village. The stoning, based on a true story, took place in 1986, but the small-mindedness and hate-filled religiosity are medieval.

The Stoning of Soraya M. is an indictment of Islamic fundamentalism and misogyny in post-Revolution Iran. The outrage of the film derives from the fact that this cruel execution is prescribed by Sharia law. Yet we all know that Islamic fundamentalists don’t have a corner on religious intolerance and hateful violence. It’s one of the paradoxes of human history that religious faith, the wellspring of morality and universal love, is also the source of so much cruelty and injustice, including cold-blooded murder.

Why is it that religious belief and teaching do not lead to moral action? What is it about religious thinking that it can create both kindness and hatefulness from the same basic beliefs? Philosophers and theologians have struggled for centuries over this riddle of human behavior, and more recently, psychological scientists have begun applying their experimental tools to explore this baffling truth. Two of these experts on religious cognition, Jesse Lee Preston and Ryan Ritter of the University of Illinois at Urbana-Champaign, have an original hypothesis about the disconnection between religion and morality, and some preliminary evidence to back it up.